The authors propose to continue the follow-up of 51,529 male health professionals, aged 40 to 75 years in 1986, to address a series of dietary hypotheses related to risk of coronary heart disease, stroke, and peripheral vascular disease. Diet has been assessed in 1986, 1990, and 1994 by a semiquantitative food frequency questionnaire developed and refined by the group over the last 15 years. Detailed studies in a subsample of participants demonstrate that this questionnaire performs well; the average correlation between the questionnaire and 14 days of diet recording for 16 nutrients of interest was 0.66. This study population has substantial variation in dietary intake, for example, fat intake varies from 25% to 42% of calories between extreme quintiles. Body fat distribution (assessed by waist and hip circumferences) has been measured twice (1987 and 1996) and weight is updated during every 2-year cycle. The first three follow-up cycles are complete; with a total questionnaire response of 94%. With the use of the National Death Index and cooperation of professional organizations, mortality follow-up is virtually complete. In the past five years, 24 papers (published or in press) were produced in the field of cardiovascular disease and related conditions, addressing such risk factors as obesity, smoking, and vitamin E, carotene, fish, fiber, and fat intake. The authors plan to continue following the cohort by questionnaires mailed at two-year intervals to update exposure information and ascertain nonfatal events. The proposed continuation is a highly cost-effective for studying diet and cardiovascular disease because funds for mailing and processing of the questionnaire and archiving of blood samples (n=18,000 collected) are provided from other sources (CA55075, DK45779, CA58684). Reported cases of nonfatal MI, stroke, peripheral arterial disease and cancer are documented with hospital records or pathology reports. Fatal events are identified by next-of-kin, postal service, or the National Death Index and confirmed by hospital records and other additional information. During the fourteen years of follow-up represented by this continuation the authors project a total of 2,068 cases of fatal or nonfatal myocardial infarction, 578 cases of stroke, and 745 cases of peripheral arterial occlusive disease. They will have substantial power to evaluate a series of continuing and new specific hypotheses to quantify dose-response relationships, and to assess the impact of change in diet and anthropometric variables using repeated measurements.